1. Field of the Invention
The present invention relates to an electronic system having a portable electronic apparatus such as a book type portable computer and an external expansion unit used to expand the function of this electronic apparatus.
2. Description of the Related Art
A book or notebook type computer is easy to carry and can be freely used, even in places where no commercial power supply is available, by using a battery pack incorporated in the computer.
A computer of this type has a case designed compact to improve portability, and hence has limitations on the standard function as compared with a desktop computer. For this reason, a portable computer has a plurality of connectors and ports for function expansion on the rear surface of the case. When such a conventional computer requires a function which the computer does not have, a peripheral device such as a hard disk drive or a mouse is connected to a corresponding one of the connectors and ports, thereby adding a new function to the computer.
The function of a computer is expanded either by directly connecting a peripheral device to the computer or by indirectly connecting it to the computer via an external expansion unit having connectors and ports which can be connected to a plurality of peripheral devices. The computer to which the external expansion unit can be connected has a first interface connector for relaying signals. The external expansion unit serves to relay signals exchanged between the computer and peripheral devices, and has a mount portion to which the computer is detachably coupled. This mount portion has a first surface on which the case of the computer is mounted, and a second surface opposing the rear surface of the case. A second interface connector electrically connected to the connectors and ports is arranged on the second surface. The second interface connector is fitted to the first interface connector when the computer is coupled to the external expansion unit. With this fitting operation, the computer is electrically connected to the external expansion unit.
The external expansion unit includes a hook for maintaining the connection between the first and second interface connectors. The hook is supported on the external expansion unit to be movable between a lock position where the hook is hooked on the rear surface of the computer to pull the computer toward the second surface and a lock release position where the hook is released from the rear surface. When the hook is moved to the lock position after the computer is placed on the first surface, the computer is pulled toward the second surface, and the first and second interface connectors are fitted to each other.
In the conventional external expansion unit, the hook for maintaining the fitted state of the first and second interface connectors is arranged on the second surface, and the hook is hooked on the rear surface off the computer. For this reason, if the front end portion of the computer is raised while the computer is coupled to the external expansion unit, an excessive bending force may be applied to the engaging portion between the hook and the computer, and the load on the hook greatly increases.
In such a case, the hook may be deformed. If the hook is deformed, an excessive force is applied to the fitting portion between the first and second interface connectors. As a result, the first and second interface connectors may be damaged, or these interface connectors may be disengaged from each other to cancel the electrical connection between the computer and the peripheral device. Especially when the connection between the external expansion unit and the computer is canceled while the external expansion unit is in use, important data may be erased, or an operation error may occur in the computer.
A portable computer has a keyboard for inputting information and commands. The keyboard is arranged on the upper surface of the case of the computer. The keyboard includes a flat keyboard panel and a large number of keys supported on the upper surface of the keyboard panel. A keyboard mount port in which the keyboard panel is fitted is formed in the upper surface of the case. The keyboard mount port has a seat portion for receiving the peripheral portion of the keyboard panel. The seat portion has a rectangular, frame-like shape. A plurality of portions of the peripheral portion of the keyboard panel are screwed to the seat portion.
According to this arrangement, however, when the keyboard is to be fixed to or removed from the case, a large number of screws must be turned. For this reason, it takes much labor and time to mount/remove the keyboard. In addition, since a large number of boss portions for receiving the screws must be arranged in the keyboard mount port, the structure of the keyboard mount port is complicated. Consequently, the need for a large number of boss portions as well as a large number of screws leads to an increase in the manufacturing cost and weight of the computer.
Some known portable computer has an icon arranged on the upper surface of the case. This icon has a plurality of display portions for displaying the contents of the operation state and function of the computer in graphic patterns. These display portions are arranged in a row on the upper surface of the case. A plurality of light-emitting diodes for lighting the display portions of the icon are housed in the case. The light-emitting diodes are arranged in a row to be adjacent to each other in the case and oppose the respective display portions.
According to the icon having such an arrangement, while the computer is in operation, only display portions corresponding to the contents of the current operation state and function are turned on upon reception of light from the corresponding light-emitting diodes. Therefore, the operator can know the contents of the operation state and function of the computer by watching the display portions in the ON state.
According to this conventional icon, however, since the plurality of display portions are arranged to be adjacent to each other, light from a light-emitting diode for a given display portion is sometimes guided to an adjacent display portion. Consequently, it is difficult to discriminate the display portion in the ON state from the display portion in the OFF state. As a result, visibility of the icon deteriorates.
In the portable computer, the connectors and ports for function expansion are covered with a connector cover while corresponding peripheral devices are not used. This connector cover is mounted on the case to be pivotal between a closing position where the connector cover becomes continuous with the case on substantially the same plane and an opening position where the connector cover is tilted outward from the case to a near-horizontal position. The connector cover has an engaging pawl. When the connector cover is pivoted to the closing position, the engaging pawl is hooked on the case to hold the connector cover at the closing position.
According to this conventional arrangement, however, in order to close the connector cover, the operator must completely push the connector cover to the closing position with his/her finger tip, and hook the engaging pawl to the case. That is, in order to close the connector cover, a reliable pivoting operation is required. This is one of the factors which cause a deterioration in the operability of the connector cover.
In addition, the conventional connector cover held at the closing position by hooking the engaging pawl to the case. Especially since the engaging pawl is integrally formed with the connector cover by using a synthetic resin material, the engaging pawl may be broken if the connector cover is repeatedly opened/closed. If the engaging pawl is broken, the connector cover cannot be held at the closing position, and dust tends to adhere to the connectors and the ports. This adhesion of dust is a cause for interference with electrical connection between a peripheral device and the computer.